It is known practice that agricultural tractors when operating with heavy attached implements attached to the rear, such as, for example, a plow, are equipped with an additional weight or an additional mass or a balance weight at the forward end of the tractor. Such a balancing system with a balance weight can be performed with a massive single balance weight (for example 900 kg) or several smaller balance weights (of, for example, 50 kg each). Usually the balance weights are arranged at a location provided for it at the forward part of the vehicle body and rigidly installed at that location. This is usually connected with considerable expense and cannot be accomplished without costly additional equipment (fork lift, crane, lifting arrangement, etc.), to assemble or disassemble the balance weights, so that the balance weights offer only few or costly possibilities, of varying the additional load applied to the front axle or to conform optimally to varying conditions or operating conditions. As a practical matter, this leads to operation with the same balance weight or the same added mass and that thereby the tractor is not optimally balanced along the way. Moreover, this can be accompanied by other disadvantages: basically higher fuel consumption as well as a lower capacity for added load with extremely heavy balance weights. An increased vehicle length and reduced mobility due to the attached balance weights that are arranged at the forward part of the vehicle body. A relatively high center of gravity of the vehicle since the balance weight is arranged, as a rule, ahead of the vehicle body and above the front axle. A high danger potential for accidents connected to it during operation on public roads, especially for passenger vehicles, since the balance weight is attached at a relative high level as compared to a passenger vehicle, so that these either roll over or that unprotected areas (windows, roof) collide with the balance weight.
Solutions are known in the state of the art with which an attempt is made to solve this problem. In that way, it is known practice, for example, to apply a front hydraulic solution, particularly a front hitch, in which an additional weight or a balance weight can be applied simply and easily for balancing if necessary. Such front hydraulic arrangements however only provide a fixed location for the balance weight, so that the aforementioned problems are considered only partially.
It is also known practice, furthermore, to apply a balancing by a balance weight or an additional weight and to make this conform to the required or the prevailing operating conditions, so that the arrangement of the weight on the vehicle is variable and in particular a movement of the weight in the longitudinal direction of the vehicle is possible.
Such an adjustable arrangement on an agricultural tractor is disclosed by U.S. Pat. No. 4,322,094A1. Here a balance weight is shifted hydraulically in the longitudinal direction; it is connected to the plate located on the underside of the vehicle body. This arrangement is connected with a high construction cost and solves the aforementioned problems only partially.
In that way, DE 3223990 A1 discloses an agricultural tractor, that is provided with a hydraulically driven parallelogram linkage at the side of the vehicle body, with which a supplemental weight can be moved ahead of the vehicle body primarily in the longitudinal direction from an upper position close to the vehicle to a lower position more distant from the vehicle. The disadvantage here is that the center of gravity of the supplemental weight in its position close to the vehicle is located relatively high due to the configuration of the linkage. Moreover, the arrangement occupies much space at the side of the vehicle to a great disadvantage.
In addition DE 10 2005 040 954 A1 discloses a balancing system on an agricultural vehicle, in which a balance weight can be shifted from a position close to the vehicle to a position distant from the vehicle by means of a front hitch. The disadvantage here is that the balance weight is located at a relatively high center of gravity in its position close to the vehicle, which lies above the front axle of the vehicle. So that here too the aforementioned disadvantages are not overcome.